Automatic overfeed furnace stoker



4' Sheets-Sheet l E. C. JOHNSON AUTOMATIC OVERFEED FURNACE STOKER Filed May 14, 1928 Jan. 27, 1931.

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Jan. 27, 1931. E Q JOHNSON 1,790,425

AUTOMATIC OVERFEED FURNACE STOKER Filed May 14. 1928 4 Sheets-Sheet 2 E i E. a L/Omwn/ i@ UM 4 www@ 4 Sheets-Sheet 3 m N wm.

Jan. 27, 1931. E. c. JOHNSON AUTOMATHIC OVERFEED FURNACE lSTOKER Filed May 14, 1928 Jan. 27, 1931. E. c. JoHNsoN 1,790,425

AUTOMATIC OVERFEED FURNACE STOKER Filed May 14, 192e 4 sheets-Sheet 4 Patented Jan. 27, 1931 UNITED STATES PATENT ol-Flcly ELMER C. JOHNSON, OF BOISE, IDAE() AUTOMATIC OVERFEED FURNACE STOKER Application filed May 14, 1928. Serial No. 277,501.

provide a portable automatic Stoker, whichwill feed the fuel through the feed door of the 10 furnace, and in which the fuel is prevented from clogging in thefeed hopper.

A further lobject ofthe invention resides in providing an improved stoker in which air will be automatically supplied both to the ash pit and to the space above the grate for aiding in the complete combustion of the fuel.

Astill further object of the invention is to provide for the protection of the apparatus from the heat of the fire and at the same time to furnish additional air to the combustion chamber.

With the foregoing and other objects in view, the invention will be more fully described hereinafter, and will be more particularly pointed out in the claim appended hereto.

In the drawings, wherein like symbols refer to like or corresponding parts throughout the several views,

Figure 1 is a side elevation with parts broken away, showing an improved automatic overfeed furnace stoker constructed in accordance with the present invention, and indicated as applied to the furnace shown in dotted lines.

Figure 2 is a front view of the same with parts broken away.

Figure 3 is a vertical section taken on the line 3 3 in Figure 1.

Figure 4 is a longitudinal vertical fragmentary section taken on an enlarged scale through the hopper and feed tube.

Figure 5 is a horizontal section taken through the feed tube.

Figure 6 is a plan view of an improved grate construction which may be used in connection with the stoker.

Figure 7 is a vertical section taken on the line 7 7 in Figure 6, and

Figure 8 is a similar view taken on the line 8*-8 in Figure 7.

Referring more particularl to the drawings 10 designates a hopper into which the fuel is loaded; and 11 represents the feed tube which communicates with the lower end of the hopper, receives the fuel therefrom and delivers the fuel to the furnace, which is indicated by the dotted lines 12 in Figure l.

The feed tube 11 is supported at such elevation that it will enter the fire box door of the furnace, or in other words the usual door through which the fuel is customarily shovv eled into the furnace; and for this purpose the entire device is mounted, as a unit, upon a Wheeled or portable frame or support, the construction of which will be referred to more particularly hereinafter.

As shown in Figures 4 and 5, the feed tube 11 is traversed by the feed worm 13, the shaft 14 of which projects beyond the rear wall 15 of the tube, Where it receives the bevel gear wheel 16. This bevel gear Wheel is mounted adjacent the bearing 17 and is provided with a collar-17 extending about the shaft 14 and aflixed to the shaft as by a shearing pin 18. The shaft may also be provided with a thrust bearing 19. v

The shaft, gear wheel 16 or its extension hub 17 are provided with an eccentric pin 20, to which is coupled a link 21 pivoted at its upper end toa lever 22 extending through a slot 23 in the rear wall of the hopper 10. The lever is fulcrumed at 24 in the hopperand is coupled to an appropriate agitating device. As shown the lever 22 is pinned or otherwise secured to a vertical agitating rod 25 and diagonal braces 26 and 27 are pivoted to the lever and to the agitating rod above and below the point'l of connection made between the agitating bar and lever. The movement of the agitating bar 25 may be guided and restrained by the straps 28.

The forward end of the feed tube 11 is protected by an air sleeve 29 of an internal diameter slightly greater than the external diameter of the tube, and provided with the internal lugs or feet 30 at spaced circumferential points and'at both ends of the sleeve for the purpose of sustaining the sleeve in spaced relation with the tube, whereby to afford an annular air passage open at its inner end to the combustion chamber of the furnace and at its, outer end to the atmosphere. A set screw 31 or other fastening device may be employed to hold the sleeve 29 in its adjusted position upon the feed tube. This sleeve 29 subserves the further function of supporting the steelor other plate 32 for closing the front of the furnace when the automatic Stoker is moved up into place. The plate 32 may be secured to a flange 33 extending outwardly from the rear end of the sleeve 29 and affixed thereto as by bolts 34 or other appropriate fastenings.

The sleeve 29 is further utilized as a means for supporting the air induction nozzle 35. This nozzle is preferably formed in one piece with the sleeve, and may be cast with it in one operation and it preferably extends at the lower portion of the sleeve and has its delivery mouth 36 turned downwardly, as shown in Figure 4, and flattened horizontally,as shown in Figure 22 whereby to deliver the air in a comparatively narrow sheet which will diverge as it leaves the nozzle and spread throughout the entire bed of coals. The downward inclination given this blast or sheet of air will cause it to penetrate the re bed and activate it forcibly and quickly. The air is delivered to the nozzle through a flexible conduit 37 under the control; of a suitable damper 38.

" bevel gear wheel 50. The latter gear Wheell The air is supplied froma fan or blower 39 driven by the electric or other motor 40. The air discharge trunk 41 of the blpwer is shown, in Figures 2 and 3, as passing up from the blower in a substantial semi-circle to reach the nozzle connection 35 and then to extend down, where it is continued into the flexible hose 42, which extends to the ash pit, as indicated in Figure 1. The motor 40 may be controlled from automatic switches both in the furnace room and in the com' artment to be heated in accordance with the ual control system. One of the automatic switches is indicated at 43 in Figure 1. The motor shaft 42 is provided with a pulley 43a and is mounted in appropriate bearings held in the carriage. The pulley 43a is arranged to drive a belt 44 engaged with a larger pulley 45 and on the worm shaft 46.

The worm wheel 47 is indicated in dotted lines in Figure 1 and this worm Wheel is mounted upon a shaft 48 carrying the bevel pinion 49 which is disposed in mesh with the is affixed to the lower end of a shaft 51 having at its upper end the bevel pinion 52 disposed in mesh with the bevel gear wheel 16.

'It will be understood that the worm may be driven by any other appropriate connections and source of power.

The motor fan unit and Worm gearing are shown as mounted in appropriate bearings on a shelf 53 of the carriage. The upper table 54 of the carriage is adapted to support the hopter pins 61 are adapted to pass through perforations in the legs and selected perforations 60 in the shanks 59. This affords a leveling adjustment.

The hopper 10 is adapted to be received into the upper end ofthe supplementary hopper 62, open at opposite ends in alinement with the feed tube 11 to permit the feed tube to pass therethrough and having a concave cradle portion 63 for receiving and supporting the lower side of the feed tube directlyA beneath the hopper.

The table is provided with the inwardly and upwardly inclined supports and guards 64 and 65 having out-turned flanges or feet 66 at their lower ends for enabling same to be secured to the table. The upper free convergent ends of these devices engage in the angle portions 67 of the complemental hopper whereby to reinforce the hopper and aid in sustaining the weight of the fuel which might otherwise tend to expand the side walls of the complemental hopper 62.

Referring now particularly to Figures 6, 7 and 8, these figures show a form of grate, which it is proposed to use in connection with the stoker. The grate 7() is removable and will preferably be cast in sections, as indicated in Figure 6. The grate is mounted within, and below the upper edge of a fire pot 71, a ledge 72 being preferably formed to receive and sustain the grate sections. These sections preferably consist of a number of radial grate bars terminating short of the center in order to permit the perforated air nozzles 73 to project up through this center portion. way of a pipe 74 with the flexible hose connection 42 to the ash pit. The fire pot is su ported upon a pedestal 75 having a base 6 and is provided with an ash removing tube 77 having a spiral conveyor 78 therein. The purpose of the fire pot and grate narrangement is to bridge the fire in a coked form. The air is delivered at a point on a level with or above the grate. The device is applicable to practically any domestic furnace or` boiler installation.

After installation, this fire pot unit is sealed up at the ash pitdoor opening and the pipe 74 is coupled to the flexible steel tubing 42. The spiral ash remover 78 is provided with a triangular extension 79 at the front of the furnace, below and out of the way of The nozzle 7 3 communicates by llt the air duct. A handle is adapted to be fitted to this extension to enable the movement of the spiral conveyor and the feeding of the ashes out through the tube 77. All foreign drafts are eliminated and an accurate control of the fire may be had at all times through the stoker.

In the operation of the device, the automatic stoker may or may not be used in connection with the improved fire pot arrangement. Whenever the temperature falls below a predetermined minimum, by either automatic switch of the dual system, current is automatically turned into the electric motor. The rotation of this motor will cause the operation of both the blower and feed conveyor 13, whereby both fuel and air will be supplied to the furnace. At the same time the fuel in the hopper is agitated. The agitator is particularly used where it is desired to burn wetfuel. Due 'to the fact that air is supplied both to the ash pit and above the grate, the fuel is entirely consumed and smoke is substantially eliminated. The arrangement is such that the fire maintains the air ports hot causing the incoming air to be heated, which in turn aids the combustion. The air both aids the combustion and cools and protects the parts ofthe apparatus projecting into the furnace. It is to be noted that when the motor is not in operation, although air will not be supplied through the nozzle 36, nevertheless it will 'be supplied through the sleeve 29 as the space within the sleeve is open at all times to the atmosphere.

This circulation of air will prevent burning out of the parts and also assist in the combustion. The device can be rolled away from the4 furnace when not needed or it can be moved to the coal bin for the purpose of replenishing the hopper 10.

' The machine will operate particularly well with slack or powdered coal. Possibly, it will not be necessary for the upper air blast to penetrate the re bed. The important thing is to supply this air in sucient quantity and at the proper locality to eliminate smoke. It is impossible to burn the smoke after the same is formed, but its formation is avoided suiicientlyheavy material to resist bulging.

It will be noted that the parts are entirely protected by a housin This is important from the standpoint of safety and also as a means for keeping the various machine parts free from dust, etc. The exposed gear at the rear of the spiral worm feed is also fitted with a removable housing and it would be impossible for a child or any one else to come into contact with any movable part of the machine.

It is obvious that various changes and modifications may be made in the details of construction and design of the above specifi-v cally described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claim.

What is claimed is In a furnace an automatic overfeed stoker, comprising a carriage, a hopper thereon for the fuel, a feed tube in communication with the hopper and extending therefrom into the furnace, a feed device within said tube, and a sleeve encircling the portion of the feed tube within the furnace and havin lugs thereon adapted to space the sleeve rom the feed tube, said sleeve having its inner end communicating with the interior of the furnace and the outer end communicating with the atmosphere, said sleevevalso having a downwardly extending nozzle formed integral therewith and postioned on the under side thereof and communicating with a source of air and with the interior of the furnace.

ELMER C. JOHNSON.

by igniting the volatile matter of the fuel.

The oxygen supplied by the air blast is intended to completely burn this volatile matter. The non-volatile part of the fuel, which is carbon or coke and which remains on the grate is burned by the air furnished underneath. The arrangement of parts is designed in the simplest way to eliminate the smoke and heat the home more economically and V' automatically.

The adjustment of the castors is also desirable for securing a vertical adjustment of the machine to various heights as required by the different styles of furnaces. It will not be in allI cases necessary to reinforce the hopper 10, as this hopper may be made of 

